A high current charging circuit and its use method

Abstract

The present invention belongs to the technical field of charging equipment, and specifically relates to a high-current charging circuit and a method of using the same, including an adapter interface, a buck-boost power supply unit, a charge pump charging unit, a Buck charging unit, a single-chip microcomputer, a detection circuit and a battery interface; the present invention does not require a specific charging protocol, such as a PPS protocol, so a common adapter can be used to implement charge pump fast charging, greatly improving the compatibility of charging equipment. Whether it is a product using a non-type_c interface or a device with different charging standards and interfaces, it can be charged efficiently and safely through the high-current charging circuit of the present invention.

Description

Technical Field

[0001] The present invention belongs to the technical field of charging equipment, and in particular relates to a high-current charging circuit and a method for using the same. Background Art

[0002] With the rapid development of electronic devices, consumers' requirements for charging efficiency and convenience are increasing. In terms of charging technology, PD (Power Delivery) fast charging technology has become the mainstream in the market with its high power, high efficiency and wide compatibility. As a standard for charging using type_c, PD specifies the voltage and current levels for charging. The PD3.0 standard stipulates that the maximum charging power reaches 100W (20V / 5A). According to the latest PD3.1 standard, the maximum charging power reaches 240W (48V / 5A). PD fast charging technology is mainly divided into two types: PPS (Programmable Power Supply) protocol and non-PPS protocol. Among them, during the charging process of the non-PPS protocol, the voltage of the charging head is fixed after negotiation, and dynamic voltage regulation is not supported, which limits its charging flexibility and efficiency to a certain extent.

[0003] For products that use non-type_c interfaces, traditional charging circuits often have problems such as low charging efficiency, slow charging speed, and poor compatibility. These products usually rely on specific chargers and charging cables, cannot be compatible with a variety of charging devices, and cannot make intelligent adjustments according to the real-time status of the battery during the charging process, resulting in low charging efficiency.

[0004] In addition, due to the wide variety of products with non-Type_C interfaces, their charging interfaces and charging standards are also different, which brings great challenges to the design of charging circuits. Traditional charging circuits often cannot meet the charging requirements of multiple interfaces and standards at the same time, resulting in poor versatility and scalability of charging equipment. Summary of the invention

[0005] In view of the fact that charging circuits using non-type-c interface products in the prior art often have problems such as low charging efficiency, slow charging speed and poor compatibility, the present invention provides a high-current charging circuit and a method of using it to solve the above technical problems.

[0006] In a first aspect, the present invention provides a high-current charging circuit, including an adapter interface, a buck-boost power supply unit, a charge pump charging unit, a Buck charging unit, a single-chip microcomputer, a detection circuit, and a battery interface;

[0007] The input end of the buck-boost power supply unit and the input end of the detection circuit are both connected to the external adapter through the adapter interface, the communication end of the buck-boost power supply unit is connected to the first end of the single-chip microcomputer, the output end of the buck-boost power supply unit is connected to the input end of the charge pump charging unit and the input end of the Buck charging unit, the output end of the detection circuit is connected to the second end of the single-chip microcomputer, the communication end of the charge pump charging unit and the communication end of the Buck charging unit are both connected to the first end of the single-chip microcomputer, and the output end of the charge pump charging unit and the output end of the Buck charging unit are connected to the external battery to be charged through the battery charging interface.

[0008] Further improvements of the technical solution include that the buck-boost power supply unit includes a voltage conversion chip of model TPS55287, the input pin of the voltage conversion chip is connected to the external adapter through the adapter interface, the enable pin, voltage programming pin and current programming pin of the voltage conversion chip are connected to the microcontroller through the I2C interface or the SPI interface, and the output pin of the voltage conversion chip is connected to the input end of the charge pump charging unit and the input end of the BUCK charging unit; the microcontroller can control the voltage conversion chip to perform output voltage programming and output current programming.

[0009] A further improvement of the technical solution is that the step size of the programmed output voltage is 10 millivolts, and the step size of the programmed output current is 50 milliamperes.

[0010] A further improvement of the technical solution is that the charge pump charging unit includes a battery charging chip of model SC8571, and the input voltage range of the charge pump charging unit is 6V-21V, and the output voltage range is 6V-10V.

[0011] A further improvement of the technical solution is that the Buck charging unit includes a battery charging chip of model BQ25672. The battery charging chip in the Buck charging unit can perform battery voltage detection, battery current detection, battery temperature detection and input voltage detection on the external battery to be charged; the battery charging chip is connected to the microcontroller via an I2C interface or an SPI interface.

[0012] A further improvement of the technical solution is that the single chip microcomputer adopts a single chip microcomputer of model STM32F103C8T6.

[0013] A further improvement of the technical solution is that the detection circuit includes a resistor R1, an operational amplifier U1, a resistor R2, a Zener diode D1 and a resistor R3, the first end of the resistor R1 is connected to the external adapter through the adapter interface, the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1, the inverting input end of the operational amplifier U1 is connected to the first end of the resistor R2 and the cathode of the Zener diode D1, the anode of the Zener diode D1 is grounded, the second end of the resistor R2 is connected to the external Vcc power supply, the output end of the operational amplifier U1 is connected to the single-chip microcomputer, and the output end of the operational amplifier U1 is connected to the non-inverting input end of the operational amplifier U1 through the resistor R3.

[0014] In a second aspect, the present invention provides a method for using the high current charging circuit according to any one of the above items, comprising:

[0015] When the microcontroller detects that an external adapter is inserted through the detection circuit, the microcontroller reads the power parameters of the external battery to be charged in the EEPROM chip and configures the output default voltage and current of the buck-boost power supply unit through the I2C interface;

[0016] The detection circuit detects whether the voltage of the inserted external adapter reaches a first preset voltage value Vth_in;

[0017] If so, the output voltage of the detection circuit jumps from a low level to a high level;

[0018] When the microcontroller detects that the output voltage of the detection circuit is at a high level, it controls the enable pin of the buck-boost power supply unit to pull the level high, and the buck-boost power supply unit outputs the configured default voltage and current;

[0019] The single chip microcomputer reads the voltage parameters of the external battery to be charged detected by the Buck charging unit through the I2C interface, and determines the charging stage of the external battery to be charged according to the read voltage parameters;

[0020] The buck-boost power supply unit is configured with a corresponding output voltage according to the current charging stage of the external battery to be charged, and after the configuration is completed, the charging unit corresponding to the current charging stage is controlled according to the preset rules to charge the external battery to be charged; the charging unit includes a charge pump charging unit and a Buck charging unit.

[0021] A further improvement of the technical solution is that the buck-boost power supply unit is configured with a corresponding output voltage according to the current charging stage of the external battery to be charged, and after the configuration is completed, the charging unit corresponding to the current charging stage is controlled according to a preset rule to charge the external battery to be charged, and the method specifically includes:

[0022] When the voltage of the external battery to be charged is less than the second preset voltage value Vth_1 or greater than the third preset voltage value Vth_3, and the third preset voltage value Vth_3 is greater than the second preset voltage value Vth_1, it is determined that the external battery to be charged is in the trickle charging stage or the constant voltage charging stage, and the single-chip microcomputer configures the output voltage of the buck-boost power supply unit to be the first preset output voltage Vout2 through the I2C interface, and the first preset output voltage Vout2 takes the middle value of the external adapter voltage and the current voltage of the external battery to be charged; after the configuration is completed, the single-chip microcomputer controls the enable pin of the Buck charging unit to be pulled high, and turns off the charge pump charging unit, and charges the external battery to be charged through the Buck charging unit;

[0023] When the read voltage of the external battery to be charged is greater than the second preset voltage value Vth_1 and less than the third preset voltage value Vth_3, it is determined that the external battery to be charged is in the constant current charging stage, and the single chip microcomputer configures the output voltage of the buck-boost power supply unit to be the second preset output voltage Vout3 through the I2C interface. The second preset output voltage Vout3 is twice the current voltage of the external battery to be charged, and the current is 6C, where C is the charge and discharge rate of the lithium battery; the single chip microcomputer controls the closing of the Buck charging unit, and controls the enable pin of the charge pump charging unit to be pulled high, and charges the external battery to be charged through the charge pump charging unit.

[0024] Further improvements of this technical solution also include:

[0025] In the process of charging the external battery to be charged through the charge pump charging unit, the single chip microcomputer regularly reads the charging voltage of the external battery to be charged detected in the Buck charging unit through the I2C interface, and uses the read charging voltage of the external battery to be charged as the reference voltage, and adds 20mV to the reference voltage as the output voltage of the buck-boost power supply unit;

[0026] During the charging process of the external battery to be charged, the single-chip microcomputer reads the battery temperature parameter of the external battery to be charged detected in the Buck charging unit through the I2C interface. When the read battery temperature parameter is greater than the first preset battery temperature value Vtem_h, the single-chip microcomputer controls the Buck charging unit or the charge pump charging unit to stop charging through the I2C interface. When the read battery temperature parameter is less than the first preset battery temperature value Vtem_l, charging is resumed.

[0027] The beneficial effects of the present invention are:

[0028] Wide compatibility: This solution does not require a specific charging protocol, such as the PPS protocol, so a common adapter can be used to implement charge pump fast charging, greatly improving the compatibility of charging devices. Whether it is a product with a non-type_c interface or a device with different charging standards and interfaces, it can be charged efficiently and safely through the high-current charging circuit of the present invention.

[0029] Flexible charging voltage: Through the built-in buck-boost power unit, the present invention can dynamically adjust the output voltage to meet the needs of different charging stages. This flexibility not only improves charging efficiency, but also reduces energy loss during charging and prolongs the battery life.

[0030] Efficient charging current: Compared with traditional charging solutions, the present invention can enable the charging circuit to have a larger charging current through the buck-boost power supply unit, and can fully charge the battery faster.

[0031] Intelligent charging management: The MCU communicates with the buck-boost power supply unit, charge pump charging unit and Buck charging unit through the I2C or SPI interface, and can read the battery charging status, voltage, current and temperature in real time. Based on this information, the MCU can intelligently adjust the charging strategy to ensure the safety and efficiency of the charging process.

[0032] In addition, the invention has a reliable design principle, a simple structure and a very broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a schematic block diagram of a high current charging circuit according to an embodiment of the present invention.

[0035] Figure 2 This is the schematic diagram of the detection circuit.

[0036] Figure 3 is a schematic flow chart of a method according to an embodiment of the present invention.

[0037] 110 is a buck-boost power supply unit, 120 is a charge pump charging unit, 130 is a Buck charging unit, 140 is a single chip microcomputer, and 150 is a detection circuit. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0040] The key terms appearing in the present invention are explained below.

[0041] I2C interface, its full English name is Inter-Integrated Circuit, the corresponding Chinese meaning is integrated circuit bus. This is a serial communication protocol developed by Philips (now NXP Semiconductors) in the early 1980s for short-distance, low-speed data transmission between integrated circuits (ICs). The I2C bus uses two lines: the serial clock (SCL) line and the serial data (SDA) line. By controlling the high and low level timing on these two lines, the signals required by the I2C bus protocol are generated for data transmission.

[0042] SPI interface, its full English name is Serial Peripheral Interface, the corresponding Chinese meaning is serial peripheral interface. This is a high-speed, full-duplex, synchronous communication bus. The standard SPI interface uses only 4 pins, including SCK (clock), MOSI (master output slave input), MISO (master input slave output) and SS (slave select, some chips are also called CS, namely Chip Select). It is mainly used for communication between microcontrollers (MCU) and peripheral devices such as EEPROM, FLASH, real-time clock (RTC), digital signal processors (DSP), etc. It has the advantages of being simple and easy to use, fast communication speed, and supporting multiple master and slave devices.

[0043] like Figure 1As shown, the present invention provides a high-current charging circuit, including an adapter interface, a buck-boost power supply unit, a charge pump charging unit, a Buck charging unit, a single-chip microcomputer, a detection circuit and a battery interface; the input end of the buck-boost power supply unit and the input end of the detection circuit are both connected to an external adapter through the adapter interface, the communication end of the buck-boost power supply unit is connected to a first end of the single-chip microcomputer, the output end of the buck-boost power supply unit is connected to the input end of the charge pump charging unit and the input end of the Buck charging unit, the output end of the detection circuit is connected to the second end of the single-chip microcomputer, the communication end of the charge pump charging unit and the communication end of the Buck charging unit are both connected to the first end of the single-chip microcomputer, and the output end of the charge pump charging unit and the output end of the Buck charging unit are both connected to an external battery to be charged through a battery charging interface.

[0044] Specifically, the buck-boost power supply unit includes a voltage conversion chip of model TPS55287 and external capacitors, inductors, resistors and other components required for the normal operation of the chip; the input pin of the voltage conversion chip is connected to the external adapter through the adapter interface, the enable pin, voltage programming pin and current programming pin of the voltage conversion chip are connected to the single-chip microcomputer through the I2C interface or the SPI interface, and the single-chip microcomputer can control the working state of the unit by controlling the enable pin of the voltage conversion chip, and the output pin of the voltage conversion chip is connected to the input end of the charge pump charging unit and the input end of the BUCK charging unit; the single-chip microcomputer can control the voltage conversion chip to program the output voltage and output current. Among them, the step size of the programmed output voltage is 10 millivolts, and the step size of the programmed output current is 50 milliamperes. The main function of this unit is to convert the input voltage of the external adapter to a suitable voltage to charge the external battery to be charged (including lithium batteries).

[0045] In addition, the charge pump charging unit includes a battery charging chip model SC8571, and peripheral devices such as resistors and capacitors required for the normal operation of the chip; and the battery charging chip is a 4:2 charging chip with an input voltage range of 6V-21V and an output voltage range of 6V-10V; in addition, the battery charging chip has protection functions such as input voltage overvoltage, input current overcurrent, output voltage overvoltage, battery voltage overvoltage and battery current overcurrent, and can output interrupt signals when these functions trigger protection.

[0046] In addition, the Buck charging unit includes a battery charging chip model BQ25672, as well as peripheral devices such as resistors, capacitors, and inductors required for the normal operation of the chip; the battery charging chip in the Buck charging unit can detect the battery voltage, battery current, battery temperature, and input voltage of the external battery to be charged; the battery charging chip is connected to the microcontroller via an I2C interface or an SPI interface. In addition, the battery charging chip has an enable pin, which is used to control whether the battery charging chip starts charging the lithium battery.

[0047] Furthermore, the single-chip microcomputer adopts a single-chip microcomputer of model STM32F103C8T6, and the components such as resistors, capacitors, crystal oscillators, power supplies, etc. required for the normal operation of the chip. At the same time, an EEPROM chip is externally connected to the single-chip microcomputer to store the specification parameters of the external battery to be charged.

[0048] like Figure 2 As shown, the detection circuit includes a resistor R1, an operational amplifier U1, a resistor R2, a voltage-stabilizing diode D1 and a resistor R3. The first end of the resistor R1 is connected to the external adapter through the adapter interface, the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1, the inverting input end of the operational amplifier U1 is connected to the first end of the resistor R2 and the cathode of the voltage-stabilizing diode D1, the anode of the voltage-stabilizing diode D1 is grounded, the second end of the resistor R2 is connected to the external Vcc power supply, the output end of the operational amplifier U1 is connected to the single-chip microcomputer, and the output end of the operational amplifier U1 is connected to the non-inverting input end of the operational amplifier U1 through the resistor R3.

[0049] like Figure 3 As shown, the present invention provides a method for using the high current charging circuit based on any one of the above items, comprising:

[0050] Step 310, when the single-chip microcomputer detects that an external adapter is inserted through the detection circuit, the single-chip microcomputer reads the power parameters of the external battery to be charged in the EEPROM chip, and configures the output default voltage and current of the buck-boost power supply unit through the I2C interface;

[0051] Step 320, the detection circuit detects whether the voltage of the inserted external adapter reaches the first preset voltage value Vth_in; if so, go to step 330;

[0052] Step 330, the output voltage of the detection circuit changes from a low level to a high level;

[0053] Step 340, when the single-chip microcomputer detects that the output voltage of the detection circuit is at a high level, it controls the enable pin of the buck-boost power supply unit to pull up the level, and the buck-boost power supply unit outputs the configured default voltage and current;

[0054] Step 350, the single chip microcomputer reads the voltage parameters of the external battery to be charged detected by the Buck charging unit through the I2C interface, and determines the charging stage of the external battery to be charged according to the read voltage parameters;

[0055] Step 360, configure the corresponding output voltage for the buck-boost power supply unit according to the current charging stage of the external battery to be charged, and after the configuration is completed, control the charging unit corresponding to the current charging stage to charge the external battery to be charged according to the preset rules; the charging unit includes a charge pump charging unit and a Buck charging unit.

[0056] Specifically, a corresponding output voltage is configured for the buck-boost power supply unit according to the current charging stage of the external battery to be charged, and after the configuration is completed, a charging unit corresponding to the current charging stage is controlled according to a preset rule to charge the external battery to be charged, and the method includes:

[0057] When the voltage of the external battery to be charged is less than the second preset voltage value Vth_1 or greater than the third preset voltage value Vth_3, and the third preset voltage value Vth_3 is greater than the second preset voltage value Vth_1, it is determined that the external battery to be charged is in the trickle charging stage or the constant voltage charging stage, and the single-chip microcomputer configures the output voltage of the buck-boost power supply unit to be the first preset output voltage Vout2 through the I2C interface, and the first preset output voltage Vout2 takes the middle value of the external adapter voltage and the current voltage of the external battery to be charged; after the configuration is completed, the single-chip microcomputer controls the enable pin of the Buck charging unit to be pulled high, and turns off the charge pump charging unit, and charges the external battery to be charged through the Buck charging unit;

[0058] When the read voltage of the external battery to be charged is greater than the second preset voltage value Vth_1 and less than the third preset voltage value Vth_3, it is determined that the external battery to be charged is in the constant current charging stage, and the single chip microcomputer configures the output voltage of the buck-boost power supply unit to be the second preset output voltage Vout3 through the I2C interface. The second preset output voltage Vout3 is twice the current voltage of the external battery to be charged, and the current is 6C, where C is the charge and discharge rate of the lithium battery; the single chip microcomputer controls the closing of the Buck charging unit, and controls the enable pin of the charge pump charging unit to be pulled high, and charges the external battery to be charged through the charge pump charging unit.

[0059] In addition, the method of use also includes the process of charging the external battery to be charged through the charge pump charging unit, the microcontroller periodically reading the charging voltage, charging current and battery temperature information of the external battery to be charged detected in the Buck charging unit through the I2C interface, and using the read charging voltage of the external battery to be charged as the reference voltage, and adding 20mV to the reference voltage as the output voltage of the buck-boost power supply unit.

[0060] In addition, the usage method also includes that during the charging process of the external battery to be charged, the microcontroller reads the battery temperature parameter of the external battery to be charged detected in the Buck charging unit through the I2C interface; when the read battery temperature parameter is greater than the first preset battery temperature value Vtem_h, the microcontroller controls the Buck charging unit or the charge pump charging unit to stop charging through the I2C interface; and when the read battery temperature parameter is less than the first preset battery temperature value Vtem_l, charging is resumed.

[0061] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A high current charging circuit, characterized in that: It includes an adapter interface, a buck-boost power supply unit, a charge pump charging unit, a Buck charging unit, a single chip microcomputer, a detection circuit and a battery interface; The input end of the buck-boost power supply unit and the input end of the detection circuit are both connected to the external adapter through the adapter interface, the communication end of the buck-boost power supply unit is connected to the first end of the single-chip microcomputer, the output end of the buck-boost power supply unit is connected to the input end of the charge pump charging unit and the input end of the Buck charging unit, the output end of the detection circuit is connected to the second end of the single-chip microcomputer, the communication end of the charge pump charging unit and the communication end of the Buck charging unit are both connected to the first end of the single-chip microcomputer, and the output end of the charge pump charging unit and the output end of the Buck charging unit are both connected to the external battery to be charged through the battery charging interface; The detection circuit includes a resistor R1, an operational amplifier U1, a resistor R2, a voltage-stabilizing diode D1 and a resistor R3. The first end of the resistor R1 is connected to an external adapter through an adapter interface, the second end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1, the inverting input end of the operational amplifier U1 is connected to the first end of the resistor R2 and the cathode of the voltage-stabilizing diode D1, the anode of the voltage-stabilizing diode D1 is grounded, the second end of the resistor R2 is connected to an external Vcc power supply, the output end of the operational amplifier U1 is connected to a single-chip microcomputer, and the output end of the operational amplifier U1 is connected to the non-inverting input end of the operational amplifier U1 through the resistor R3.

2. The high current charging circuit according to claim 1, characterized in that: The buck-boost power supply unit includes a voltage conversion chip of model TPS55287, the input pin of the voltage conversion chip is connected to an external adapter through an adapter interface, the enable pin, voltage programming pin and current programming pin of the voltage conversion chip are connected to a single-chip microcomputer through an I2C interface or an SPI interface, and the output pin of the voltage conversion chip is connected to the input end of a charge pump charging unit and the input end of a BUCK charging unit; the single-chip microcomputer can control the voltage conversion chip to perform output voltage programming and output current programming.

3. The high current charging circuit according to claim 2, characterized in that: The output voltage can be programmed in steps of 10 mV and the output current can be programmed in steps of 50 mA.

4. The high current charging circuit according to claim 1, characterized in that: The charge pump charging unit includes a battery charging chip of model SC8571. The input voltage range of the charge pump charging unit is 6V-21V, and the output voltage range is 6V-10V.

5. The high current charging circuit according to claim 1, characterized in that: The Buck charging unit includes a battery charging chip model BQ25672. The battery charging chip in the Buck charging unit can perform battery voltage detection, battery current detection, battery temperature detection and input voltage detection on the external battery to be charged; the battery charging chip is connected to the microcontroller through an I2C interface or an SPI interface.

6. The high current charging circuit according to claim 1, characterized in that: The single chip microcomputer used is STM32F103C8T6.

7. A method for using the high current charging circuit according to any one of claims 1 to 6, characterized in that: include: When the microcontroller detects that an external adapter is inserted through the detection circuit, the microcontroller reads the power parameters of the external battery to be charged in the EEPROM chip and configures the output default voltage and current of the buck-boost power supply unit through the I2C interface; The detection circuit detects whether the voltage of the inserted external adapter reaches a first preset voltage value Vth_in; If so, the output voltage of the detection circuit jumps from a low level to a high level; When the microcontroller detects that the output voltage of the detection circuit is at a high level, it controls the enable pin of the buck-boost power supply unit to pull the level high, and the buck-boost power supply unit outputs the configured default voltage and current; The single chip microcomputer reads the voltage parameters of the external battery to be charged detected by the Buck charging unit through the I2C interface, and determines the charging stage of the external battery to be charged according to the read voltage parameters; The buck-boost power supply unit is configured with a corresponding output voltage according to the current charging stage of the external battery to be charged, and after the configuration is completed, the charging unit corresponding to the current charging stage is controlled according to a preset rule to charge the external battery to be charged; the charging unit includes a charge pump charging unit and a Buck charging unit; According to the current charging stage of the external battery to be charged, the buck-boost power supply unit is configured with a corresponding output voltage, and after the configuration is completed, the charging unit corresponding to the current charging stage is controlled according to a preset rule to charge the external battery to be charged, and the method specifically includes: When the voltage of the external battery to be charged is less than the second preset voltage value Vth_1 or greater than the third preset voltage value Vth_3, and the third preset voltage value Vth_3 is greater than the second preset voltage value Vth_1, it is determined that the external battery to be charged is in the trickle charging stage or the constant voltage charging stage, and the single-chip microcomputer configures the output voltage of the buck-boost power supply unit to be the first preset output voltage Vout2 through the I2C interface, and the first preset output voltage Vout2 takes the middle value of the external adapter voltage and the current voltage of the external battery to be charged; after the configuration is completed, the single-chip microcomputer controls the enable pin of the Buck charging unit to be pulled high, and turns off the charge pump charging unit, and charges the external battery to be charged through the Buck charging unit; When the read voltage of the external battery to be charged is greater than the second preset voltage value Vth_1 and less than the third preset voltage value Vth_3, it is determined that the external battery to be charged is in the constant current charging stage, and the single chip microcomputer configures the output voltage of the buck-boost power supply unit to be the second preset output voltage Vout3 through the I2C interface. The second preset output voltage Vout3 is twice the current voltage of the external battery to be charged, and the current is 6C, where C is the charge and discharge rate of the lithium battery; the single chip microcomputer controls the closing of the Buck charging unit, and controls the enable pin of the charge pump charging unit to be pulled high, and charges the external battery to be charged through the charge pump charging unit.

8. The method of use according to claim 7, characterized in that: Also includes: In the process of charging the external battery to be charged through the charge pump charging unit, the single chip microcomputer regularly reads the charging voltage of the external battery to be charged detected in the Buck charging unit through the I2C interface, and uses the read charging voltage of the external battery to be charged as the reference voltage, and adds 20mV to the reference voltage as the output voltage of the buck-boost power supply unit; During the charging process of the external battery to be charged, the single-chip microcomputer reads the battery temperature parameter of the external battery to be charged detected in the Buck charging unit through the I2C interface. When the read battery temperature parameter is greater than the first preset battery temperature value Vtem_h, the single-chip microcomputer controls the Buck charging unit or the charge pump charging unit to stop charging through the I2C interface. When the read battery temperature parameter is less than the first preset battery temperature value Vtem_l, charging is resumed.

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